Behind the outage: Crews restore thousands before search ends with faulty insulator

May 9 2016, 13:47 PM

They searched for hours on foot, off-road vehicle and by helicopter. Finally, at 1 am on Monday, crews spotted a flash on a transmission pole more than 21 metres high while running a test of the line that revealed the faulty equipment to blame for Sunday’s large outage in the Kennebecasis Valley.

It was a single cracked insulator. Just one small piece of equipment, but it caused an unusual kind of widespread power outage that inconvenienced many of our customers on Mother’s Day while our crews and operators worked feverishly to find the cause and safely restore power.

When 22,000 customers in Rothesay, Quispamsis and surrounding areas lost power around 7:30 a.m. on Sunday May 8, NB Power’s operating centre immediately identified the issue being transmission-related. We sent out specialized transmission line crews to determine a cause and a plan to restore affected customers.

While crews searched for a cause, our operators began switching groups of customers to other energized lines, bringing as many customers back online as quickly and safely as possible.

By 10:00 a.m., more than 16,000 customers were back online. As the day went on and the weather conditions allowed, crews safely transferred the customer demand from one substation to another, allowing NB Power to restore power to customers by smaller group size as crews continued to search for the cause of the outage.

By 3:30 p.m. 1,000 customers remained without power.

 

The damaged insulator which caused the transmission outage in Kennebecasis Valley region. This insulator was 21 metres in the air, and this crack was difficult to identify in the daylight. 

During situations like these, we work with customers to minimize the impact to hospitals, nursing homes, stores and arenas. Yesterday, we spoke with the Mayor of Rothesay, Bill Bishop and appreciate all of his support in communicating with residents of the area.  

Before we could safely restore power to the remaining 1,000 customers we needed to test the transmission line stability, which meant  we had to deliberately bring approximately 5,000 customers offline to safely complete the test to ensure we could add the additional electricity demand of 1000 more customers to the line. For this reason, some customers previously restored experienced two additional, brief outages around 3:30 and 5 p.m.

We were able to transfer the remaining customer load to surrounding lines in order to restore everyone by 9:30pm.

It was a rare occurrence that we were not able to identify the cause of the outage throughout the day. NB Power ground and air patrol crews searched the line for obstructions, or equipment problems but could not see anything. We had people stationed at certain locations along the transmission line in the afternoon to search for the root cause of the problem while the system operators at our Energy Control Centre energized and de-energized the line as part of the testing.

Knowing what the issue was allowed us to make necessary repairs Monday morning, and transfer the 1000 customers back to the Fairvale substation without interruption.

We appreciate the continued patience of our customers during this outage on Mother’s Day, while our crews worked diligently to ensure we got everyone back online as quickly and safely as was possible under the circumstances.

Click here to read more information on how we restore power during major outages.